1. Field of the Invention
The invention relates in general to elevator systems, and more specifically to elevator systems having a display which indicates the service direction in which an elevator car will proceed from a floor it is serving.
2. Description of the Prior Art
An elevator system conventionally includes a display for each car of the system which indicates to prospective passengers the service direction in which the elevator car will proceed from a floor it is serving. The display, usually referred to as a "hall lantern", may be mounted above or adjacent to the hatch door of the associated elevator car, at each floor the elevator car serves, or it may be carried by the elevator car in a location where it will be visible from the hallway when the car and hatch doors are open.
The hall lanterns usually include one incandescent lamp for each travel direction with the appropriate lamp being energized to indicate the travel direction of the car away from the associated floor. A gong is connected in series with the common line from each up and down hall lantern fixture, such that it produces a single sound when the associated up or down lamp is energized.
When the service direction indicator is hall mounted, the up or down lantern for a floor is energized before the actual arrival of the car at the floor, usually when the car initiates slowdown to stop at the floor. The selected hall lantern remains energized until the doors start to close, or until they are fully closed, as desired.
The incandescent lamps of conventional hall lantern fixtures are of the high voltage type and susceptible to failure due to the high in-rush current and also to the long and delicate lamp filaments.
It would be desirable to improve the hall lanterns of an elevator system by enabling the long life solid state display devices to be used, such as light emitting diodes, liquid crystals, and the like, but the hall lantern display must provide visible and audible signals which are suitable for the general public, including the handicapped. It is also important that the economic advantage to be achieved by reducing the number of service calls to replace burned out incandescent lamps, are not offset by the initial cost of the new hall lanterns.